There is known a method for producing graft copolymers of protein fiber, such as wool or silk, with vinyl monomers, comprising the steps of impregnating the protein fiber with an aqueous solution of ferrous salt, washing off excessive ions of ferrous iron, impregnating the fiber with an aqueous solution of a reducing agent, such as sodium hydrosulfite or dioxide of thiourea, washing off the excessive reducing agent, and grafting vinyl monomers to the protein fiber from an aqueous solution or aqueous emulsion of a vinyl monomer, containing hydrogen peroxide.
The method under review is disadvantageous in that it is carried out as a multistage process resulting in excessive amounts of effluents. Besides, the above-mentioned reducing agents cannot provide for a sufficiently high rate of graft polymerization, which, in turn, does not make it possible to intensify the production of graft copolymers.
There is further known a method for producing graft copolymers of cellulose or protein fiber, such as wool, with vinyl monomers, comprising the steps of impregnating cellulose or protein fiber with an aqueous solution of a mixture of ferrous salt and a reducing agent which is formaldehyde sulfoxylate of sodium, washing off excessive reducing agent and excessive ions of ferrous iron, and grafting vinyl monomers to cellulose or protein fiber from an aqueous solution or aqueous emulsion of a vinyl monomer, containing hydrogen peroxide.
The latter method is disadvantageous in that the reducing agent does not ensure a sufficiently high rate of graft polymerization and thus does not make it possible to intensify the production of graft copolymers; another disadvantage of this method is that it does not provide for continuous production of graft copolymers of cellulose.